Chapter 6 Rational Exponents and Radical Functions - 6.5 Graph Square Root and Cube Root Functions - 6.5 Exercises - Mixed Review - Page 451: 43

$$x=\frac{4\sqrt{7}}{7},\:x=-\frac{4\sqrt{7}}{7}$$

Solving the equation by isolating $x$, we find: $$7x^2=16 \\ x^2=\frac{16}{7} \\ x=\sqrt{\frac{16}{7}},\:x=-\sqrt{\frac{16}{7}} \\ x=\frac{4\sqrt{7}}{7},\:x=-\frac{4\sqrt{7}}{7}$$